Categorie: Uncategorized

Seismic shots with explosives have been used for years in the search for oil. Alaska is crisscrossed with all but indelible “seismic” disruptions of tundra. The reserves of Prudhoe Bay were discovered in this manner. Dynamite in the populous East could irritate the public, so the universities and the U.S.G.S. use a behemoth called Vibroseis to conference room groningen shiver the timbers of the earth. One of the first discoveries the vibrations reported was that the Brevard Zone is relatively shallow and the crust below it is American rock that does not in any vague way reflect a continent-to-continent suture. Africa was nowhere in the picture. The Brevard Zone proved to be the toboggan-like front end of a large and essentially horizontal thrust sheet. Plate-tectonic theorists accommodated this news by moving the suture fifty miles east. The new edge of Africa was under Kings Mountain. Seismic shots took the stitches out of Kings Mountain. ‘When we got the data for the Brevard” -as Leonard Harris liked to tell the story-“they pushed the suture to Kings Mountain, and when we got data for that they said the suture must be under the coastal plain, and now that we are getting data for the coastal plain they say it must. be in tl1e continental shelf. Well, we’ve got data out there, too.” Up and conference room amsterdam down the Appalachians, wherever such data were collected, thrust sheets were seen to have moved in a northwesterly direction, and much of the thrusting had never been suspected before.

Confronted with a mountain sawed in half, a traveller would naturally speculate about how that might have happened-as had the Indians before, when they supposedly concluded that the Minisink had once been “a deep sea of water.” Samuel Preston agreed with the Indians. In i828, in a letter to Hazard’s Register of Pennsylvania, Preston referred to the Water Gap as “the greatest natural curiosity in any part of the State.” He went on to hypothesize that “from the appearance of so much alluvial or made land above the mountain, there must, in some former period of the world, have been a great dam against the mountain that formed all the settlements called Minisink into a lake, which extended and backed the water at least fifty miles.” And therefore, he worked out, “from the water-made land, and distance that it appears to have backed over the falls in the river, the height must, on a moderate calculation, have been between one hundred and fifty and two co-working space groningen hundred feet, which would have formed a cataract, in proportion to the quantity of water, similar to Niagara.” Preston was a tourist, not a geologist. The first volume of Charles Lyell’s Principles of Geology, the textbook that most adroitly explained the new science to people of the nineteenth century, would not be published for another two years, let alone cross the sea from London. All the more remarkable was Preston’s Hypothesis. Like many an accomplished geologist who would follow, Preston made excellent sense even if he was wrong. Withal, he had the courage of his geology. “If any persons think my hypothesis erroneous,” he concluded, “they may go and examine for themselves ….T he Water Gap will not run away.” While sediments accumulated slowly in the easygoing lowlands of the late Silurian world, iron in the rock was oxidized, and therefore the rock turned red. Alternatively, it could have been co-working space amsterdam red in the first place, if it weathered from a red rock source. There were dark-hued muds and light silts in the outcrop, settled from Silurian floods. There were balls and pillows, climbing ripples, flow rolls, and mini-dunes-multihued structures in the river sands. Maroon. Damask. Carmine. Rouge.

At depths of nine thousand to fifteen thousand feet, she discovered, conodonts would turn light brown in roughly ten million years. If they spent ten million years at, say, eighteen thousand feet, they would be dark brown. In comparable amounts of time but at greater and greater depths, they would turn black, gray, opaque, white, clear as crystal. Anita also cooked conodonts in pressure bombs, because it had been suggested to her that the pressures of great tectonism-the big dynamic events in the crust, with mountains building and whole regions being kneaded like dough-might also affect conodont colors. Her experiments convinced her that pressure has little effect on color; heat is what primarily causes it to change. Of course, plenty of heat is produced by deep burial during major tectonic events. Her conodonts from New Jersey were black and from Kentucky pale essentially flexplek huren groningen because huge disintegrating eastern mountain ranges had buried the near ones very deep and the far ones scarcely at all. The East is for the most part the wreckage of the Ancestral Appalachians, and-as is exemplified in the Devonian rock of New York-the formations are thickest close to where the mountains stood. A continuous sedimentary deposit that is thousands of feet thick in eastern Pennsylvania may be ten feet thick in Ohio. Where oil was first discovered in western Pennsylvania, it was seeping out of rocks and running in the streams. It is of a character and purity so remarkable that people used to buy it and drink it for their health. Anita looked at conodont samples from rock that surrounded this truly exceptional oil. In the temperature range of eighty to a hundred and twenty degrees, they were in the center of the petroleum window. They were golden brown. With a year of tests flexplek huren amsterdam nm, with Kodachrome pictures, with graphs and charts of what she called her “wind-tunnel models,” she was prepared to tell her story. The Geological Society of America was to meet in Florida in November, i974, and she arranged to deliver a paper there. “I prepared carefully-I always do-so I wouldn’t phumpfer. But the G.S.A. meeting was not momentous. They were academics, and not particularly knowledgeable about exploration techniques.” Five months later, scarcely knowing what to anticipate, she went to Dallas and spoke before the American Association of Petroleum Geologists.

A day would come when I would pick up Anita Harris at the home of a cousin of hers in Morganville, New Jersey, and drive across the Narrows Bridge to Brooklyn. She had not seen her neighborhood for twenty-five years. Her cousin, Murray Srebrenick, who gave us coffee before we left, was more than a little solicitous toward us, and even somewhat embarrassed, as if he were in the presence of people with an uncorrectable defect. He, too, had grown up in
Brooklyn, and now, as an owner and flexplek huren leeuwarden operator of trucks, he supported his suburban life hauling clothes to Seventh Avenue. On runs through the city to various warehouses, he and his drivers knew what routes to avoid, but often enough they literally ran into trouble. Crime was part of his overhead, and as he rinsed the coffee cups he finally came out with what he was thinking and pronounced us insane. He spoke with animation, waving a pair of arms that could bring down game. Old neighborhood or no old neighborhood, he said, he would not go near Williamsburg, or for that matter a good many other places in Brooklyn; and he reeled off stories of open carnage that might have tested the stomach of the television news. I wondered what it might be like to die defending myself with a geologist’s rock hammer. Anita, for her part, seemed nervous as we left for the city. Twenty-five years away, she seemed afraid to go home. It was an flexplek huren schiphol August day already hot at sunrise. “In Williamsburg, I lived at 381 Berry Street,” she said as we crossed the big bridge. “It was the worst slum in the world, but the building did have indoor plumbing. Our first apartment there was a sixth-floor walkup. The building was from the turn of the century and was faced with red Triassic sandstone.” Brooklyn was spread out before us, and Manhattan stood off to the north, with its two sets of skyscrapers three miles apart-the ecclesiastical spires of Wall Street, and beyond them the midtown massif. Anita asked me if I had ever wondered why there was a low saddle in the city between the stands of tall buildings.

His criterion could only have been that they seemed compelling to him. His guyots, he had by now decided, were volcanoes that grew at spreading centers, where they protruded above the ocean surface and were attacked by waves. With the moving ocean floor they travelled slowly down to the abyssal plains and went on eventually to “ride down into the jaw crusher” of the deep trenches, where they were consumed. “The earth is a dynamic body with its surface constantly changing,” he wrote, and he agreed with others that the force driving it all must be heat from deep in the mantle, moving in huge revolving cells (an idea that had been around in one flexplek huren groningen form or another since i839 and is still the prevailing guess in answer to the unresolved question: What is the engine of plate tectonics?). Hess reasoned also that the heat involved in the making of new seafloor is what keeps the ocean rises high, and that moving outward the new material gradually cools and subsides. The rises seemed to be impermanent features, the seafloor altogether “ephemeral.” “The whole ocean is virtually swept clean (replaced by new mantle material) every three hundred to four hundred million years,” he wrote, not then suspecting that ocean crust is actually consumed in half that time. “This accounts for the relatively thin veneer of sediments on the ocean floor, the relatively small number of volcanic seamounts, and the present absence of evidence of rocks older than Cretaceous in the flexplek huren amsterdam oceans.” In ending, he said, “The writer has attempted to invent an evolution for ocean basins. It is hardly likely that all of the numerous assumptions made are correct. Nevertheless it appears to be a useful framework for testing various and sundry groups of hypotheses relating to the oceans. It is hoped that the framework with necessary patching and repair may eventually form the basis for a new and sounder structure.” In i963, Drummond Matthews and Fred Vine, of Cambridge University, published an extraordinary piece of science that gave to Hess’s structure much added strength. Magnetometers dragged back and forth across the seas had recorded magnetism of two quite different intensities. Plotted on a map, these magnetic differences ran in stripes that were parallel to the mid-ocean ridges.

The group was called Eocene and was interested in scavenging old mines. Deffeyes pointed out to them that while new gold strikes were still occurring in the world and new gold mines were still being developed, no major silver mine had been discovered since i915. The pressure for silver was immense. Dentistry and photography used two-thirds of what there was, and there were no commercial substitutes. “We’ve been wiped out. We’ve gone through it, just as we have gone through magnesium and bromine. You can raise the price of silver all you want to but you won’t have a new mine.” He predicted that as prices went up silver would probably outperform gold. The potentialities in the secondary recovery of silver appeared to him to be a lot more alluring than working through tailings for gold. Eocene engaged him as a consultant, to help them scavenge silver. Now far zakelijke energie above the basin, we were on the thin line we had seen from below, a track no wider than the truck itself, crossing the face of the mountain. It curved into reentrants and out around noses and back into reentrants and out to more noses. I was on the inboard side, and every once in a while as we went around a nose I looked across the hood and saw nothing but sky-sky and the summits of a distant range. We could see sixty, seventy miles down the valley and three thousand feet down the mountain. The declivity was by no means sheer, just steep-a steepness, I judged, that would have caused the vehicle, had it slipped off the road, to go end over end enveloped in flame at a hundred yards a bounce. My hands slid on the wheel. They were filmed in their own grease. The equanimous Deffeyes seemed to be enjoying the view. He said, “Where did you learn to drive a truck?” “Not that it’s so god-damned difficult,” I told him, “but this is about the first time.” Before igoo, the method used in this country to extract silver from most ores was to stamp the rock to powder in small stamp . mills, then stir the powder zakelijke energie vergelijken into hot salt water and mercury, and, after the mercury had attracted the silver, distill the mercury. In i887, a more thorough extraction process had been developed in England whereby silver ores were dissolved in cyanide. The method moved quickly to South Africa and eventually to the United States.

Lyell, Cuvier, Conybeare, Phillips, von Alberti, von Humboldt, Desnoyers, d’Halloy, Sedgwick, Murchison, Lapworth, Smith (William “Strata” Smith): the geologists who extended Hutton’s insight and built this time scale conjoined their names in the history of the science in a way that would not be repeated for more than a hundred years, until a roster of comparable length-Hess, Heezen, McKenzie, Morgan, Wilson, Matthews, Vine, Parker, Sykes, Ewing, Le Pichon, Cox, Menard-would effect the plate-tectonics revolution. The system of rock immediately above the Paleozoic, in which all that Permian life failed to reappear, was typified by three formations in Germany-certain sandstones, limestones, and marly shales-that ran like a striped flag through the Black Forest, the Rhine Valley, and lent the name Triassic to forty-two million years. In the Triassic, the earliest zakelijke energie subdivision of the Mesozoic era, two families of reptiles that had survived the Permian Extinction began to show patterns of unprecedented growth. This would continue for a hundred and fifty million years-through the Jurassic and out to the end of Cretaceous time, when the “fearfully great lizards,” on the point of disappearance, would reach their greatest size, not to be surpassed until epochs that followed the Eocene development of whales. European geologists studying the massive limestones of the Jura-the gentle mountains of the western cantons of Switzerland and of Franche-Comte-related the copious displays of ancient life there to comparable assemblages elsewhere in the world, and called them all Jurassic. A primordial bird appeared in the Jurassic. It had claws on its wings and teeth in its bill and a reptile’s long tail sprouting feathers. Its complete performance envelope as a flier was to climb a tree and jump. Physicists, zakelijke energie vergelijken chemists, and mathematicians, taking note of all the nomenclatural inconsistencies-of time named for mountain ranges, time named for savage tribes, time named for a country here, a county there, an oblast in the Urals-have politely, gently, suggested that, in this one sense only, the time scale seems archaic, seems, if one may say so, out of date.

He camped beside the trail\ farther east. He attracted the Donners. He attracted Reeds, Kesebergs, Murphys, McCutchens, drew them southward away from thJ main trek and into the detentive scrub oak made fertile by the limestones of the Wasatch. The Donners were straight off the craton{solid and trusting, from Springfield, Illinois. Weeks were used hacking a path through the scrub oaks, which were living barbed fre. Equipment was abandoned on the Bonneville flats to lighten up loads in the race against thirst. Even in miles, the nigher route proved longer than the one it was shortcutting, on the way to a I sierra that was named for snow. 1 Deffeyes and I passed graffiti on the Bonneville flats. There being nothing to carve in zakelijke energie and no medium substadtial enough for sprayed paint, the graffitists had lugged cobbles out onto the hard mud-stones as big as grapefruit, ballast from the interstate-and in large dotted letters had written their names: Ross, D Aw N, DoN , JUDY, MARK, MOON, ERIC, fifty or sixty miles of names. YARD SALE. Eric’s lithography was in basalt and dolomite, pieces of Grayback Mountain, apparently, pieces of the Stansburys. His name, if it sits there a century or so, will eventually explode. Salt will work into the stones along the grain boundaries. When this happens, water evaporates out of the salt, and salt crystals keep collecting and expanding until they explode the rock. In Death Valley are thousands of little heaps of crumbs that were once granite boulders. Salt exploded them. Salt gets into fence zakelijke energie vergelijken posts and explodes them at the base. Near tl1e far side of Utah, the flats turned blinding white, cornsnow white, and revolving winds were making devils out of salt. Over the whiteness you could see the salt go off the curve of the earth. When the drivers of jet cars move at Mach .9 over the Bonneville Salt Flats, they feel that they are always about to crest a hill. Dig into the salt and it turns out to be a crusty white veneer, like cake icing, more than an inch thick-an almost pure sodium chloride. Below it are a few inches of sand-size salt particles, and below them a sort of creamy yogurt mud that is the color of blond coffee. In much the manner in which these salts were left behind by the shrinking outline of the saline lake, there were times around the edges of North America when the shrinking ocean stranded bays that gradually dried up and left plains of salt.

Those who will make the subject their field of major study become interested after they arrive. It is up to Deffeyes to interest them-and not a few of them-or his department goes into a subduction zone. So his eyes search the hall. People out of his course have been drafted by the Sacramento Kings and have set records in distance running. They have also become professors of geological geophysics at Caltech and of petrology at Harvard. Deffeyes’ own research has gone from Basin and Range sediments to the floor of the deep sea to unimaginable events in the mantle, but his enthusiasms are catholic and he appears to be less attached to any one part of the zakelijke energie vergelijken story than to the entire narrative of geology in its four-dimensional recapitulations of space and time. His goals as a teacher are ambitious to the point of irrationality: At the very least, he seems to expect a hundred mint geologists to emerge from his course-expects perhaps to turn on his television and see a certified igneous petrographer up front with the starting
Kings. I came to know Deffeyes when I wondered how gold gets into mountains. I knew that most old-time hard-rock prospectors had little to go on but an association of gold with quartz. And I knew the erosional details of how gold comes out of mountains and into the rubble of streams. What I wanted to learn was what put the gold in the mountains in the first place. I asked a historical geologist and a geomorphologist. They both recommended Deffeyes. He explained that gold is not merely zakelijke energie vergelijken rare. It can be said to love itself. It is, with platinum, the noblest of the noble metals-those which resist combination with other elements. Gold wants to be free. In cool crust rock, it generally is free. At very high temperatures, however, it will go into compounds; and the gold that is among the magmatic fluids in certain pockets of interior earth may be combined, for example, with chlorine. Gold chloride is “modestly” soluble, and will dissolve in water that comes down and circulates in the magma. The water picks up many other elements, too: potassium, sodium, silicon. Heated, the solution rises into fissures in hard crust rock, where the cooling gold breaks away from the chlorine and-in specks, in flakes, in nuggets even larger than the eggs of geese-falls out of the water as metal. Silicon precipitates, too, filling up the fissures and enveloping the gold with veins of silicon dioxide, which is quartz.

Now, with its completion, the project represents the stratum of time i978-1998. Its first four components were published in i981, i983, i986, and i993. A fifth and final essay appears in this volume to fill a significant gap. Nowhere in the structure I have referred to was there much of anything about the midcontinent. It was there in a broad and general way. It was there in a number of time lines shot across the country in various periods, epochs, and ages. But it was not there in any kind of rock-to-rock progression. In mid-America, there are few surface rocks. That initial over-all composition, purporting to traverse the nation, deliberately overlooked a large piece of the nation-Chicago to Cheyenne. If the rocks were scarce, the zakelijke energie tectonics were scarcer. For more than a billion years, little to nothing had happened there. Even so, I felt a measure of guilt about the omission, and contemplated what to do to close that epic caesura. The answer came with the geophysical insights of recent years, the combined advances in many fields, from radiometric dating to computer science, that have enabled geologists to see the midcontinent itself forming and developing in the Precambrian eons. This was the basement of the world, under construction. I thought it a good idea to travel between Cheyenne and Chicago down there. I did so, in a way, with W. R. Van Schmus, of the University of Kansas.
Because the entire composition in all its parts was written in the form of journeys, set pieces, flashbacks, biographical sketches, and histories of the human and lithic kind-intended as an unfolding piece of writing and not as a catalogue of geologic topics-the text firmly refrained from offering a way in which a reader could easily turn to something like the basic set piece on plate theory or the basic set piece on zakelijke energie vergelijken geologic time. In the interest of the composition, such topics were not discretely labelled. That is why I am writing a narrative table of contents. In this inclusive volume, I am trying to have things both ways. While leaving the text unparcelled and continuous, I want to explain up front not only how the project came to be, and how it evolved across the twenty years, but also what’s what and where. Basin and Range, as the opening story, is the primer. It contains the long set piece on the nature and history of plate tectonics-what it is, who figured it out, and how.